Which practice best prevents flame spread in concealed spaces?

Which practice best prevents flame spread in concealed spaces?

• A. Fireblocking.
• B. Insulating with fiberglass only.
• C. Sealing with drywall compound.
• D. Painting the area.

Answer: (A)

Fireblocking interrupts the vertical path of flame and hot gases through concealed spaces, creating a physical barrier that slows or stops flame spread between levels and around openings. By filling and sealing these cavities with fire-resistant material, you limit air movement and give occupants more time to escape and firefighters a better chance to control the fire. Insulation by itself (fiberglass) only reduces heat transfer, not flame movement. Sealing with drywall compound or painting doesn’t provide a lasting barrier in concealed spaces, so they don’t prevent flame spread the way proper fireblocking does.

Fireblocking interrupts the vertical path of flame and hot gases through concealed spaces, creating a physical barrier that slows or stops flame spread between levels and around openings. By filling and sealing these cavities with fire-resistant material, you limit air movement and give occupants more time to escape and firefighters a better chance to control the fire. Insulation by itself (fiberglass) only reduces heat transfer, not flame movement. Sealing with drywall compound or painting doesn’t provide a lasting barrier in concealed spaces, so they don’t prevent flame spread the way proper fireblocking does.